1. Field of the Invention
This invention relates to high speed printers which sequentially print characters in either a first or a second direction along a selected print line.
2. Description of the Prior Art
In order to print characters by means of a print head which is driven at high speeds laterally along a print line by a stepper motor, it is necessary to closely coordinate the generation of characters by the print head with the actual position of the print head along a selected print line. U.S. Pat. No. 3,942,619 to Nordstrom and Szechy, which is hereby incorporated by reference, discloses a high speed, single direction printer. This printer utilizes a voltage controlled oscillator to ramp up the stepper motor to maximum velocity in a minimum amount of time. The same voltage controlled oscillator is also used to indicate to the character generating circuitry the approximate print head position. A single electronic signal is thus used to energize the stepper motor and to simultaneously trigger the character generating circuitry.
U.S. Pat. No. 3,970,183 to Robinson discloses a random access line printer which includes an optically read registration strip in combination with count up and count down counters.
Other related disclosure is contained in the following United States Patents. U.S. Pat. Nos. 3,891,077 (Sauerbrunn); 3,824,587 (Fowler); 3,525,094, (Leonard); 3,432,847 (Eccles, et al); 3,408,484 (Stutz); 4,037,705 (Martin, et al.); 3,967,271 (Day); 3,973,662 (Fulton).